Originally Posted by ghittner (Post 2278094)

Lunati 612/ 612 lift, 112 Deg lobe center w/ no reversion issues...duration I can find for you, great cam with excellent dock etiquette. I would run this again for a non blown application. Do you need a part #????

Originally Posted by ghittner (Post 2278086)

Yes, you need the oil cooler with the extra power. I know this sounds screwy but I have that also. The company sent me two of the one I'm using because I thought I was going to a dual engine in the future. it is a P/s and Oill cooler like stock. I also have the custom pushrods for this setup that you will need for the Merlin heads. As far as the peanut ports? My opinon is throw them away. They will never make power in the range you are looking for. NEVER. Start with the GOOD basics. This combo took my boat from 46 MPH to 63 MPH Fact on GPS.

Originally Posted by jeff1000man (Post 2278113)

Wow, that is a big cam. Is it roller or flat tappet?

Yeah, I'd like to have a part number.

Thanks.

Originally Posted by jeff1000man (Post 2278119)

WHat custom pushrods? You need custom bolts, but I have been using regular stock length pushrods and havn't had any issues.

Help me out here. My rollers are hitting the middle of the valve like they are supposed to also.

Just checking because I have not heard of this with the thickeer heads like merlins and darts etc.

Originally Posted by KAAMA (Post 2279599)

ghittner, I had a question for you back on Post #11 (first paragraph) I was kind of curious about---don't know if you may have missed it. Thanks

Originally Posted by ghittner (Post 2278124)

Roller worked awesome. 50274 LUN

Originally Posted by KAAMA (Post 2277545)

Did you also re-use the stock cast crank, 3/8" rods, and cast pistons while upgrading the HP to 425hp from the Merc 330 ??? Or did you swap to all forged internals? Do you happen to remember what RPM it made 425hp at?

About 5 years ago my cousin rebuilt his Merc 330's. He went to 461cid, retained the same stock cast cranks, 3/8" rods, and installed new cast pistons and 2-bolt main blocks. The only thing he did to upgrade the stock rods was had them shot peened, and replaced the stock rod bolts with ARP rod bolts and reconditioned, had the rotating assemblies completely balanced and the blocks align honed.

He used some old JUNK GM large oval port semi open chamber heads that he had JimV install 2.19" intake valves and 1.85" extaust valves and did some bowl/pocket port short side radius work on the heads. Funny, the 1.88" exhaust valves did not work/flow as well in that particular head because of the way the chamber was designed....the 1.88" valves actually were too large and did not flow as near as well as the smaller 1.85" exhaust valves...at least in this reference.

He used a hydraulic flat tappet cam of 218*/226* (at .050" lift) .515"/.515" lift on 110* lobes, dual plane intake manifold, Holley 830cfm carb, and had the cylinders in the blocks all "bore notched" to unshroud the valves for better flow, 8.6 comp ratio, 32* of timing, and they made 461hp @5100rpm and 510 lbs of torque at 3600rpm on Tom Earhart's dyno with car dyno tubular headers.

Torque stayed very flat up to 5000rpm. He could have used a cam with more duration, but we wanted to keep the RPM's at about 5000-5200rpm because of the cast pistons just to be safe.

The engines were installed in a 1988 32' Baja and I think it would be fair to assume that the engines have lost about 25HP going from the dyno headers to a dry piped GIL exhaust manifold in the boat. He has only tried one set of props (went from a 21" 3-blade to a 25" 3-blade) and said he picked up 10mph in the midrange and on top.

Originally Posted by drpete3 (Post 2279696)

I am curious too. What do you want for those dust collecting parts? I have a 454 mag 1989, stock.

Originally Posted by jeff1000man (Post 2279704)

Hey KAAMA, you can get away with using a lot of those stock parts out of the 330. We actually have a boat with a 10-71 blower and 100 NOS shot running 2 old short blocks off of a 330 merc. We did change the pistons, pins and bearing, but are still using stock crank and rods. We rarely break a rod or have a crank issue. We do break a lot of valves and cams that are supposed to be high end aftermarket. These engines have been to 7000. We started putting 6k limited from MSD on them. Not sure how much longer they will run, but they have 2 good seasons on them. Shouldn't be any problem fo you at all to make a 500hp motor with them.

My .02 contribution to the discusion.